Optical module

ABSTRACT

An integrated apparatus with optical/electrical interfaces and protocol converter on a single silicon substrate. The apparatus includes an optical module comprising one or more modulators respectively coupled with one or more laser devices for producing a first optical signal to an optical interface and one or more photodetectors for detecting a second optical signal from the optical interface to generate a current signal. Additionally, the apparatus includes a transmit lane module coupled between the optical module and an electrical interface to receive a first electric signal from the electrical interface and provide a framing protocol for driving the one or more modulators. Furthermore, the apparatus includes a receive lane module coupled between the optical module and the electrical interface to process the current signal to send a second electric signal to the electrical interface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S.application Ser. No. 16/813,504 filed Mar. 9, 2020, which is acontinuation and claims priority to U.S. application Ser. No. 16/431,492filed Jun. 4, 2019 (now U.S. Pat. No. 10,630,414 issued Apr. 21, 2020),which is a continuation of U.S. application Ser. No. 16/034,668 filedJul. 13, 2018 (now U.S. Pat. No. 10,355,804 issued Jul. 16, 2019), whichis a continuation of and claims priority to U.S. application Ser. No.15/694,472 filed Sep. 1, 2017 (now U.S. Pat. No. 10,050,736 issued Aug.14, 2018), which is a continuation of and claims priority to U.S.application Ser. No. 15/375,031 filed Dec. 9, 2016 (now U.S. Pat. No.9,787,423 issued Oct. 10, 2017), which is a continuation of U.S.application Ser. No. 14/625,489 filed Feb. 18, 2015 (now U.S. Pat. No.9,553,670 issued Jan. 24, 2017), which claims priority to U.S.Provisional Application No. 61/947,374 filed Mar. 3, 2014, commonlyassigned and incorporated by reference herein for all purposes.

BACKGROUND OF THE INVENTION

The present invention relates to telecommunication techniques. Moreparticularly, the present invention provides an integrated apparatuswith optical/electrical interfaces and protocol converter fortelecommunication and methods.

Over the last few decades, the use of communication networks exploded.In the early days Internet, popular applications were limited to emails,bulletin board, and mostly informational and text-based web pagesurfing, and the amount of data transferred was usually relativelysmall. Today, Internet and mobile applications demand a huge amount ofbandwidth for transferring photo, video, music, and other multimediafiles. For example, a social network like Facebook processes more than500 TB of data daily. With such high demands on data and data transfer,existing data communication systems need to be improved to address theseneeds.

Over the past, there have been many types of communication systems andmethods. Unfortunately, they have been inadequate for variousapplications. Therefore, improved communication systems and methods aredesired.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to telecommunication techniques. Morespecifically, various embodiments of the present invention provide acommunication interface that is configured to transfer data at highbandwidth over optical communication networks. In certain embodiments,the communication interface is used by various devices, such as spineswitches and leaf switches, within a spine-leaf network architecture,which allows large amount of data to be shared among servers.

In modern electrical interconnect systems, high-speed serial links havereplaced parallel data buses, and serial link speed is rapidlyincreasing due to the evolution of CMOS technology. Internet bandwidthdoubles almost every two years following Moore's Law. But Moore's Law iscoming to an end in the next decade. Standard CMOS silicon transistorswill stop scaling around 5 nm. And the internet bandwidth increasing dueto process scaling will plateau. But Internet and mobile applicationscontinuously demand a huge amount of bandwidth for transferring photo,video, music, and other multimedia files. This disclosure describestechniques and methods to improve the communication bandwidth beyondMoore's law.

Serial link performance is limited by the channel electrical bandwidthand the electronic components. In order to resolve the inter-symbolinterference (ISI) problems caused by bandwidth limitations, we need tobring all electrical components as close as possible to reduce thedistance or channel length among them. Stacking chips into so-called 3-DICs promises a one-time boost in their capabilities, but it's veryexpensive. Another way to achieve this goal in this disclosure is to usemultiple chip module technology.

In an example, an alternative method to increase the bandwidth is tomove the optical devices close to electrical device. Silicon photonicsis an important technology for moving optics closer to silicon. In thispatent application, we will disclose a high-speed electrical opticsmultiple chip module device to achieve terabits per second speed, aswell as variations thereof.

In an example, the present invention provides an integrated apparatusfor high speed telecommunication. The integrated apparatus includes asilicon photonics-based optical module configured to convert electricalsignal into optical signal for 100 Gb/s or 400 Gb/s high-ratecommunication. The optical module is configured to output one or moreoptical signals with wavelengths in a course wave length divisionmultiplex (CWDM) grid with 20 nm channel spacing, for example, a firstlaser with a first wave length having a peak of 1270 nm, a second laserhaving a second wave length having a peak at 1290 nm, a third laser witha third wave length having a peak at 1310 nm, and a fourth laser havinga fourth wavelength having a peak at 1330 nm. The optical module isalternatively configured to output one or more channel wavelengths in adense wavelength division multiplex (DWDM) grid with peak wavelengths ina c-band ranging from 1525 to 1565 nm.

In an example, each of the laser devices included in the optical modulefor generating laser wavelength at either CWDM grid or DWDM grid is DFBcharacterized with a sufficiently low noise to meet a PAM N transmissionover 100 km, whereupon N ranges from 2-8 (typically N=2^(n), i.e., 2, 4,8, etc.). In an example, each of the laser devices included in theoptical module is characterized by a RIN (CNR)<−140 dB/Hz or better. Inan example, each of the lasers is un-cooled or subject to cooling. Ifuncooled, it lowers power consumption, while leaving wavelength to“float” resulting in a lower spectral density. In another example, theoptical module further comprises a TEC (thermoelectric cooler) toprovide temperature stabilize for each of the lasers. In an example,each of the lasers is externally modulated using a Si Mach Zehndermodulator operating in a carrier depletion mode.

In an example, the optical module further comprises one or more highspeed photodetectors made of germanium and integrated on a siliconsubstrate and coupled to an optical input port for detecting one or moreincoming optical signals in the CWDM grid or DWDM grid. The siliconsubstrate comprises a fiber interface comprising a plurality ofv-grooves, each of the v-grooves coupled to a mode adaptor. Thephotodetectors are configured to convert optical signals in the CWDM orDWDM grid to electrical currents that can be digitalized.

In an example, the silicon substrate comprises a separate path for atransmitter and a receiver. In an example, the silicon substratecomprises an interface configured with a single mode optical fiber. Inan example, the laser light with each CWDM or DWDM grid wavelength ismodulated with data, and processed into a single stream of information.In an example, the optical module further comprises a modulatorconfigured for both NRZ and PAM4 modulation scheme. In another example,the optical module comprises a distributed modulator comprising aplurality of segments and a PAM4 coding is achieved via a thermometercoding. In yet another example, the NRZ modulation is achieved bydriving all the segments together. In still another example, thedistributed or segmented modulator is coupled to a limiting driverconfigured in CMOS. In yet still another example, the segmentedmodulator is configured with a segment length between 250 μm and 450 μmfor minimal device parasitics and suitable for high speed operation.

In addition, the integrated apparatus further comprises a driver, whichhas a control block, an encoder, and a distributed MZM configuration.The driver comprises a parallel array of a plurality of amplifiers, eachof which is optimized to drive a single segment of a modulator device inthe optical module. In an example, the modulator device is coupled tothe laser CWDM or DWDM grid using a flip chip configuration. In anexample, the optical module has an optical input and an optical output.In an example, the integrated apparatus has a power supply, amicrocontroller, and a transmit lane and a receive lane, the receivelane comprising a clock data recover device (CDR), forward errorcorrection device (FEC), digital signal processor device (DSP), and atransimpedance amplifier (TIA). In an example, the transmit lanecomprises a CDR, FEC, encoder device (ENC), and a driver (DRV). Further,the integrated apparatus has an electrical input interface and anelectrical output interface, each of the interfaces is configured foreither 4×10 Gb/s or 4×25 Gb/s. In another example, the optical modulehas a first multiplexer configured on the receive lane, and a secondmultiplexer configured on the transmit lane. In an example, theintegrated apparatus is provided within a QSFP-28 package comprising ametal shield for electromagnetic radiation.

In a specific embodiment, the present invention provides an integratedapparatus with optical/electrical interfaces and protocol converter on asingle silicon substrate. The apparatus includes an optical modulecomprising one or more modulators respectively coupled with one or morelaser devices for producing a first optical signal to an opticalinterface. The optical module further includes one or morephotodetectors for detecting a second optical signal from the opticalinterface to generate a current signal. Additionally, the apparatusincludes a transmit lane module coupled between the optical module andan electrical interface. The transmit lane module includes at least amodulation driver configured to receive a first electric signal from theelectrical interface and provide a framing protocol for driving the oneor more modulators. Furthermore, the apparatus includes a receive lanemodule coupled between the optical module and the electrical interface.The receive lane module includes at least a transimpedance amplifierconfigured to process the current signal to send a second electricsignal to the electrical interface. The first or second optical signalis associated with one or more wavelengths configured in a coarsewavelength division multiplex (CWDM) grid or a dense wavelength divisionmultiplex (DWDM) grid.

The present invention achieves these benefits and others in the contextof known memory technology. However, a further understanding of thenature and advantages of the present invention may be realized byreference to the latter portions of the specification and attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following diagrams are merely examples, which should not undulylimit the scope of the claims herein. One of ordinary skill in the artwould recognize many other variations, modifications, and alternatives.It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this process andscope of the appended claims.

FIG. 1 is a simplified diagram illustrating cloud data center campusinterconnections according to a prior art.

FIG. 2 is a simplified diagram of a table illustrating interconnectionvolume per section for different distances ranging from 3 meters to 80kilometers under the above cloud data center architecture.

FIG. 3 is a simplified diagram of an integrated apparatus configuredwith electrical/optical interfaces for high data-rate telecommunicationaccording to an embodiment of the present invention.

FIG. 4A is simplified diagrams of optical architecture of the integratedapparatus according to a first example of the present invention.

FIG. 4B is simplified diagrams of optical architecture of the integratedapparatus according to a second example of the present invention.

FIG. 5 is a simplified diagram of optical architecture of the integratedapparatus according to a third example of the present invention.

FIG. 6 is a simplified diagram of using a 2-to-1 power combiner forcombining two 100 GHz grid to create a 50 GHz grid according to anembodiment of the present invention.

FIG. 7 is a simplified diagram illustrating an example of 40 Gbit/s PAM4encoding implemented in the integrated apparatus according to anembodiment of the present invention.

FIG. 8 is a simplified diagram illustrating an example of 100 Gbit/sPAM4 encoding implemented in the integrated apparatus according to anembodiment of the present invention.

FIG. 9 is a simplified block diagram of packing the integrated apparatusfor high data-rate telecommunication according to an embodiment of thepresent invention.

FIG. 10 is a simplified diagram illustrating a silicon photonics opticalmodule chip layout according to an embodiment of the present invention.

FIG. 11 is a simplified diagram of a modulation driver device accordingto an embodiment of the present invention.

FIG. 12 is a simplified diagram illustrating a control scheme of MZmodulator according to an embodiment of the present invention.

FIG. 13 is a simplified diagram illustrating a preferred select tablefor modulation driver according to an embodiment of the presentinvention.

FIG. 14 is a simplified diagram illustrating PAM4 encoding schemeaccording to an embodiment of the present invention.

FIG. 15 is a simplified block diagram illustrating PAM4 encoder logicaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

This present invention relates to telecommunication techniques. Morespecifically, various embodiments of the present invention provide anintegrated apparatus with communication interface configured to transferelectrical data at high bandwidth over optical communication networks.In certain embodiments, the communication interface is used by variousdevices, such as spine switches and leaf switches, within a spine-leafnetwork architecture, which allows large amount of data to be sharedamong servers.

In the last decades, with advent of cloud computing and data center, theneeds for network servers have evolved. For example, the three-levelconfiguration that have been used for a long time is no longer adequateor suitable, as distributed applications require flatter networkarchitectures, where server virtualization that allows servers tooperate in parallel. For example, multiple servers can be used togetherto perform a requested task. For multiple servers to work in parallel,it is often imperative for them to be share large amount of informationamong themselves quickly, as opposed to having data going back forththrough multiple layers of network architecture (e.g., network switches,etc.).

Leaf-spine type of network architecture is provided to better allowservers to work in parallel and move data quickly among servers,offering high bandwidth and low latencies. Typically, a leaf-spinenetwork architecture uses a top-of-rack switch that can directly accessinto server nodes and links back to a set of non-blocking spine switchesthat have enough bandwidth to allow for clusters of servers to be linkedto one another and share large amount of data.

In a typical leaf-spine network today, gigabits of data are shared amongservers. In certain network architectures, network servers on the samelevel have certain peer links for data sharing. Unfortunately, thebandwidth for this type of set up is often inadequate. It is to beappreciated that embodiments of the present invention utilizes PAM(e.g., PAM4, PAM8, PAM12, PAM16, etc.) in leaf-spine architecture thatallows large amount (up terabytes of data at the spine level) of data tobe transferred via optical network.

The following description is presented to enable one of ordinary skillin the art to make and use the invention and to incorporate it in thecontext of particular applications. Various modifications, as well as avariety of uses in different applications will be readily apparent tothose skilled in the art, and the general principles defined herein maybe applied to a wide range of embodiments. Thus, the present inventionis not intended to be limited to the embodiments presented, but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

In the following detailed description, numerous specific details are setforth in order to provide a more thorough understanding of the presentinvention. However, it will be apparent to one skilled in the art thatthe present invention may be practiced without necessarily being limitedto these specific details. In other instances, well-known structures anddevices are shown in block diagram form, rather than in detail, in orderto avoid obscuring the present invention.

The reader's attention is directed to all papers and documents which arefiled concurrently with this specification and which are open to publicinspection with this specification, and the contents of all such papersand documents are incorporated herein by reference. All the featuresdisclosed in this specification, (including any accompanying claims,abstract, and drawings) may be replaced by alternative features servingthe same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

Furthermore, any element in a claim that does not explicitly state“means for” performing a specified function, or “step for” performing aspecific function, is not to be interpreted as a “means” or “step”clause as specified in 35 U.S.C. Section 112, Paragraph 6. Inparticular, the use of “step of” or “act of” in the Claims herein is notintended to invoke the provisions of 35 U.S.C. 112, Paragraph 6.

Please note, if used, the labels left, right, front, back, top, bottom,forward, reverse, clockwise and counter clockwise have been used forconvenience purposes only and are not intended to imply any particularfixed direction. Instead, they are used to reflect relative locationsand/or directions between various portions of an object.

FIG. 1 is a simplified diagram illustrating cloud data center campusinterconnections according to a prior art. It is known, there is nosingle design or size for a cloud data center. Topologies ofconstructing such a data center continue to evolve with technologyadvancements and cost structures. Differences of the data centerarchitecture design are driven by generation of design, location andscale. While the overall traffic flow within different data centers issimilar the design differences drive different link requirements. Datacenter development and growth typically experience three phasesincluding design, build-out and operational. Usually they are often inoperational phase simultaneously with the build-out phase.

New co-location of a data center may come online as old one is beingrefreshed in three year cycle. Infrastructure should last at least 4-6generations of refresh. New data centers and associated co-locations canbe added to meet growing demand. For data center based on OpticalEthernet, inside the data center could be as far as 2 km. Datacommunication uses multi-mode fiber (MMF) with 1 to 40Gigabit rate,though 100-400Gigbit single-mode fiber (SMF) Ethernet transmission ispossible. Outside the data center, 1 through 400Gigbit SMF Ethernet isapplicable for range from 2 to 10 km. Beyond data center topology, asshown in FIG. 1, it is a campus level where multiple data centercollocations are interconnected in a leaf-spine network architectureconnected by Metro DWDM for 10-80 km range and Core DWDM for >100 kmrange. For range less than 1000 m, each data center connects each nodeof four sections per one of multiple colocations via spine network up to2 km range. Each co-location node per section further connects aplurality of ports via leaf network in less than 20 m range whichconnects many TOR ports supported by multiple Servers in 3 m range. Theinfrastructure is designed to use a single data rate (X) and the Serverlinks are a subset of X. For example, X is 100 Gb/s, 400 Gb/s or higher.

FIG. 2 is a simplified diagram of a table illustrating interconnectionvolume per section for different distances ranging from 3 meters to 80kilometers under the above cloud data center campus interconnectionarchitecture. Each data center includes multiple co-locations and eachco-location includes four sections. The table in FIG. 2 shows theinterconnection volume from TOR to DC in the spine/leaf fiber network inwhich high cost sensitive market space on fiber-based high data-ratetelecommunication apparatus is pictured. In particular, 100 Gb/s to 400Gb/s apparatuses with integrated optical and electrical interfaces forcommunications of Long Reach (LR) leaf-to-spline, spine-to-DCR, andDCR-to-Metro using single-mode fiber connections are highly desired andwill be described in more details below.

FIG. 3 is a simplified diagram of an integrated apparatus configuredwith electrical/optical interfaces and protocol converter for highdata-rate telecommunication according to an embodiment of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. One of ordinary skill in the art wouldrecognize many variations, alternatives, and modifications. As shown,the integrated apparatus 100 is formed as a system-on-chip apparatusconfigured to convert electrical signal to optical signal or vise versafor high data-rate digital communication. The apparatus 100 includes asilicon-photonics optical module 101 having an optical interface with aninput port 105 and an output port 106, a control module 102 with a powersupply and a microcontroller or other ASIC circuits, and a transmit lanemodule 104 and a receive lane module 103. The optical module 101includes a first multiplexer 1001 configured on the receive lane toreceive a multiplexed optical signal from the input port 105 and to havemultiple photo-detectors (PDs) 1003 to convert the de-multiplexedsignals with different wavelengths into corresponding electrical currentsignals before sending to the receive lane module 103. In an embodiment,the first multiplexer 1001 is a silicon-based delay-line interferometer(DLI). In a specific embodiment, the DLI is configured to interleave amultiplexed light from one fiber into two waveguides each with a lightin different wavelength. The optical module 101 further includes asecond multiplexer 1002 configured on the transmit lane to couplemultiple DFB lasers 1004 respectively modulated by MZ modulators (MZM)1005 based on electrical signals received from and pre-processed by thetransmit lane module 104. The second multiplexer 1002 is able to combineall optical signals and output it through the output port 106 tospline-leaf fiber network. In an embodiment, the second multiplexer 1002is also a DLI served as a 2-to-1 power combiner to combined two lightsin different wavelengths (for example, two channels in CWDM or DWDM gridwith 50 GHz or 100 GHz spacing) into a multiplexed light for beingtransmitted through a single fiber. The receive lane module 103comprises a clock data recover device (CDR), a forward error correctiondevice (FEC), a digital signal processor device (DSP), and atransimpedance amplifier (TIA). The transmit lane module 104 comprises aCDR, a FEC, an encoder device (ENC), and a driver (DRV). Further, theintegrated apparatus 100 is coupled with an electrical interface 200having an input and an output configured for receiving or deliveringEthernet data with either 4×10 Gb/s or 4×25 Gb/s or higher data-rate.Based on the received electrical data, the DRV driver controls the DFBlaser 1004 to generate a light with a certain wavelength and control themodulator 1005 for modulating the light from DFB laser 1004 to carry thedata.

FIG. 4A is a simplified diagram of the integrated apparatus according toa first example of the present invention. This diagram is merely anexample, which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. As shown, two integrated apparatuses 100A and 100Bare respectively deployed at two end locations, or so-called A-end andZ-end corresponding to a leaf-to-spine (<400 m) or spine-to-DCR (<1000m) fiber network. In the example, each integrated apparatus 100A or 100Bis substantially the same as apparatus 100 depending on specificconfigurations for matching particular data rate and framing protocolformat. In an embodiment, FIG. 4A illustrate an optical architecture inwhich an output port 106A of the integrated apparatus 100A at the A-endis directly connected to an input port 105B of another integratedapparatus 100B at the Z-end without need of an optical amplifier (OA).The electrical input signals with 40 Gb/s (or 100 Gb/s rate) can becategorized to 4×10 Gbit/s (or 4×25 Gbit/s) using the integratedapparatus (100A or 100B) to convert the electrical signals to 4λ or 2λoptical signals in a NRZ or PAM4 encoding scheme. Correspondingly, theoptical signals are categorized to either 2λ×22.5 Gbaud (or 1λ×22.5Gbaud) for 4×10 Gbit/s rate and 4λ×28.125 Gbaud (or 2λ×28.125 Gbaud) for4×25 Gbit/s rate.

The integrated apparatus 100A or 100B includes one up to 4 DFB laser(s)(though only two wavelengths are shown in FIG. 4A) associated with asilicon-photonics based optical module for generating optical signalsbearing up to four wavelengths in CWDM grid around 1300 nm with 20 nmchannel spacing. The optical signals are needed to only travel adistance less than 2 km. In an embodiment, in association with thereceive lane of the optical module, a first multiplexer is included forinterleave light from a single fiber to two paths with differentwavelength. While in associated with the transmit lane of the opticalmodule, a second multiplexer is configured to be a 2-to-1 power combinerfor combining lights generated by two DFB lasers at two wavelengths intoone fiber. Each of the first multiplexer and the second multiplexer canbe made of a delay-line interferometer while operated with lighttraveling in opposite direction.

In an example, each of the laser devices included in the optical modulefor generating laser wavelength at either CWDM grid or DWDM grid is DFBcharacterized with a sufficiently low noise to meet a PAM N transmissionover 100 km, whereupon N ranges from 2-8 (typically N=2^(n), i.e., 2, 4,8, etc.). In an example, each of the laser devices included in theoptical module is characterized by a RIN (CNR) <−140 dB/Hz. In anexample, each of the lasers is un-cooled or subject to cooling. If it isuncooled, it lowers power consumption, while leaving wavelength to“float” in association with a lower spectral density. In anotherexample, the optical module further comprises a TEC (thermoelectriccooler) to provide temperature stabilize for each of the lasers. In anexample, each of the lasers is externally modulated using a Si MachZehnder modulator operating in a carrier depletion mode.

FIG. 4B is a simplified diagram of the integrated apparatus according toa second example of the present invention. This diagram is merely anexample, which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. As shown, in a second example of opticalarchitecture, two integrated apparatuses 200A and 200Z are deployedpair-wisely at an A-end and a Z-end of a DCR-to-Metro fiber network toprovide data communication with rate of 40 Gbit/s using a singlewavelength at DWDM grid generated by a DFB laser. The apparatus200A/200Z at the A/Z-end of the DCR-to-Metro fiber network includes anoptical module having an output/input port 206A/205Z fortransmitting/receiving a single wavelength (1λ) light carrying datato/from an input/output port 205Z/206A the paired apparatus 200Z/200A atZ/A-end of the network. No multiplexer is needed within the opticalmodule of the integrated apparatus 200A or 200Z.

From one data center, multiple paths can be deployed from this datacenter to multiple destination in the DCR-to-Metro network. Thus,multiple integrated apparatuses, all in pair-wise manner like 200A and200Z, can be deployed at corresponding A-end and Z-end of respectivelypaths. An optical module of each integrated apparatus at either A orZ-end is equipped with a single DFB laser for generating respectivechannel wavelength in the DWDM grid. For example, the channel wavelengthcan be one selected from all C-band wavelengths having channel spacingof 50 GHz.

From a transmission end of the DCR-to-Metro network, the laser light ateach channel wavelength is modulated into a specific optical signalbased on an electrical input signal by a MZ modulator. In an embodiment,PAM4 encoding is used for converting the electrical signal of 40 Gbit/sto an 1λ-20 Gbaud optical signal carried by a single-wavelength light.The MZ modulator (MZM) is built in the optical module of each integratedapparatus (200A or 200Z) and outputted through the corresponding outputport (e.g., 206A or 206Z) regardless that the integrated apparatus isdeployed at A-end or Z-end. Each MZ modulators is a Si Mach Zehndermodulator operated in a carrier depletion mode. All these individualsingle-wavelength lights are combined by a DWDM MUX device 300 with 50GHz channel spacing to a single fiber before being transmitted via thenetwork over distances larger than 10 km. In an embodiment, the DWDM MUXdevice 300 is able to multiplex up to 96 channels of wavelengths in aDWDM grid with 50 GHz channel spacing. In certain embodiments, opticalamplifier (OA) and dispersion compensation module (DCM) may be neededfor retaining data integrity. Other functionalities of each integratedapparatus associated with transmit lane are substantially similar towhat have been described for the integrated apparatus 100.

From a receiving end of the DCR-to-Metro network, a 50 GHZ channelspacing DEMUX device 300 is configured to de-multiplex an incomingoptical signal received from the transmission end to multiple individuallights with respective single wavelength (1λ) at a DWDM grid with 50 GHzchannel spacing. Then each single wavelength light carryingcorresponding modulated data is received via a corresponding input port(205A or 205Z) of the optical module (without being equipped amultiplexer in either receiver) of the corresponding integratedapparatus (200A or 200Z). The data carried by the single wavelengthlight is detected by a photodetector (PD) therein and further convertedto an electrical signal. Other functionalities of each integratedapparatus associated with receive lane for processing the aboveconverted electrical signal are substantially similar to what have beendescribed for the integrated apparatus 100.

In an example, each of the laser devices included in the optical moduleis characterized with a sufficiently low noise to meet a PAM Ntransmission over 100 km, whereupon N ranges from 2-8 (typicallyN=2^(n), i.e., 2, 4, 8, etc.). In an example, each of the laser devicesincluded in the optical module is characterized by a RIN (CNR) <−140dB/Hz. In an example, each of the lasers is un-cooled or subject tocooling. If uncooled, it lowers power consumption, while leavingwavelength to “float” in association with a lower spectral density. Inanother example, the optical module further comprises a TEC(thermoelectric cooler) to provide temperature stabilize for each of thelasers. In an example, each of the lasers is externally modulated usinga Si Mach Zehnder modulator operating in a carrier depletion mode.

FIG. 5 is a simplified diagram of the integrated apparatus according toa third example of the present invention. This diagram is merely anexample, which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. As shown, it is a scenario for transmitting 100Gbit/s DWDM optical signal with 28.125 GBaud under a dual wavelength(2λ) PAM4 encoding in DCR-to-Metro network. Similar to the scenarioshown in FIG. 4B, two integrated apparatus 400A and 400Z are deployed atboth A-end and Z-end of one path of DCR-to-Metro network.

In a specific embodiment, each apparatus, 400A or 400Z, unlike that onlyone DFB laser is included in each apparatus in FIG. 4B but a 50 GHz DWDMMUX device 300 must be required for combining multiple channels with 50GHz spacing, is configured to include two DFB lasers respectively set attwo wavelengths (2λ) having 50 GHz spacing but respectively shifted 25GHz apart from a standard DWDM grid with 100 GHz spacing. A DLI-basedmultiplexer in the optical module of the integrated apparatus 400A or400B first combines the modulated lights generated from two DFB lasersto one output port as a 2λ, optical signal. When multiple integratedapparatuses similar to 400A or 400B are added for providing additional2λ, optical signals, each of those additional channel wavelengths can beproperly selected from DWDM grid with 50 GHz spacing and configured tohave center wavelength of each 2λ, optical signal outputted from oneintegrated module is 100 GHz apart from that of a nearest neighbor 2λ,optical signal outputted from another integrated module of the samekind. When all these 2λ, optical signals are combined, it is able toprovide all (up to 96) channels with 50 GHz spacing. With such opticalarchitecture, a common 100 GHz MUX device 400, instead of more expensive50 GHz multiplexer, is enough to provide all required 50 GHz spacingchannels for transmitting data through the DCR-to-Metro network for 40Gbit/s or 100 Gbit/s system.

FIG. 6 is a simplified diagram of using a 2-to-1 power combiner forcombining two 100 GHz grid to create a 50 GHz grid according to anembodiment of the present invention. This diagram is merely an example,which should not unduly limit the scope of the claims. One of ordinaryskill in the art would recognize many variations, alternatives, andmodifications. In general, in the embodiments shown in previous figures(FIG. 4A, 4B, and 5), it requires a 50 GHz multiplexer for the 40 Gbit/ssystem and a 100 GHz multiplexer for the 100 Gbit/s system. In analternative embodiment, as shown in FIG. 6, to create a 50 GHz grid 609(for the 40 Gbit/s system) from two 100 GHz grids 601 and 602 a 2-to-1power combiner 605, e.g, the DLI in the optical module, to interleavelycombine two sets of channels from two 100 GHz multiplexers. Each 100 GHzmultiplexer (601 or 602) combines a set of 100 GHz spacing channels andeach channel of one set is 50 GHz apart from a corresponding channel inanother set. The trade-off for replacing the 50 GHz multiplexer with 100GHz multiplexer is that additional 3 dB gain is required from theoptical amplifier in the same optical path.

FIG. 7 is a simplified diagram illustrating an example of 40 Gbit/s PAM4encoding implemented in the integrated apparatus according to anembodiment of the present invention. This diagram is merely an example,which should not unduly limit the scope of the claims. One of ordinaryskill in the art would recognize many variations, alternatives, andmodifications. As shown, 40 Gbit/s PAM4 encoding is implemented in thetransmit lane module by using PAM encoder to couple with a FEC encoderto handle an electrical signal received via a Rx-CDR from an electricalinterface through, e.g., a 4×10 G Quad Small Form-factor Pluggable(QSFP) compact, hot-pluggable format. The PAM encoder further coupleswith a PAM driver in the transmit lane module for providing control of aPAM-based MZ modulator associated with a single DFB laser in the opticalmodule. The PAM4 encoding is implemented to driver the DFB laser togenerate an laser light modulated by the MZ modulator such that a 4×10Gibt/s rate electrical signal can be converted to a 22.5 GBaud opticalsignal at the output port of the optical module, thereby enabling 40Gbit/s rate transmission over one of four CWDM channels or up to 96 DWDMgrid channels with 50 GHz channel spacing.

In the same integrated module, as shown in FIG. 7, the PAM encoding isalso implemented in association with the receive lane module. When thePIN photodetector receives the optical signal from a single-mode fiber(after <80 km transmission), the optical signal is converted to anelectric current that is amplified by a transimpedance amplifier (TIA).Then PAM-enabled analog to digital converter (ADC) converts the analogcurrent signal to digital signal which is processed with PAM-enabledencoding algorithm by a digital signal processor (DSP). Following that,the digital signal is further processed by a clock and data recoverydevice (CDR) to remove the jitter inherited from the high data ratesystem. A FEC decoder with 7.5 dB coding gain is applied for decodingforward error correction code associated with the signal. A Tx-CDR thenis used for processing the signal before sending out through theelectrical interface in QSFP format.

FIG. 8 is a simplified diagram illustrating an example of 100 Gbit/sPAM4 encoding implemented in the integrated apparatus according to anembodiment of the present invention. This diagram is merely an example,which should not unduly limit the scope of the claims. One of ordinaryskill in the art would recognize many variations, alternatives, andmodifications. As shown, for a 100 Gb/s data rate system, PAM4 encodingimplementation needs two wavelengths (2λ) in optical mode fortransmitting 28.125 GBaud signal with 50 Gb/s per wavelength.Accordingly, a dual PAM driver is used in the transmit lane module todrive two DFB lasers in the optical module to generate two lights whichare respectively modulated by a dual MZ modulator based on PAM4 encodingprotocol to convert the corresponding electric signals received from anelectrical interface in 4×25 G CAUI-4 format. The electric signals alsoare processed by FEC encoder and PAM-enabled encoder before beingconverted to optical signals. In addition, to handle the 2λ, opticalsignals a MUX device is added to the optical module for combining twolights into one and outputting to a single fiber. In a specificembodiment, 28.125 GBaud PAM4 encoding implemented in the integratedapparatus enables 100 Gbit/s data rate optical transmission over one of4 CWDM channels or 40 DWDM channels with 100 GHz spacing.

Similarly, in the receive lane a DEMUX is firstly needed to interleavethe optical signal from the single fiber back to two separate lightswith corresponding channel wavelengths carrying the PAM4 mode signal.Accordingly, a dual PIN photodetector is used to separately detect thetwo lights with different wavelengths and respectively convert to twocurrent signals. In the receive lane module, a dual linear TIA and dualPAM-enabled ADC/DSP device are implemented for processing the currentsignal and generating a corresponding digital signal. Subsequently, aFEC device is configured to decode the signal and perform forward errorcorrection. Finally, a properly formatted electric signal is transmittedout in 4×25 Gb/s rate via the electrical interface.

FIG. 9 is a simplified block diagram of packing the integrated apparatusincluding 100 G to 400 G silicon photonics chip development for highdata-rate telecommunication according to an embodiment of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. One of ordinary skill in the art wouldrecognize many variations, alternatives, and modifications. As shown,the integrated apparatus is configured to be packaged on a singlesubstrate or interposer including a silicon photonics optical module anda receive lane module plus a transmit lane module. The silicon photonicsoptical module is packaged in a SiPho die including built-in DFB lasersto provide up to 4 laser lights with corresponding channel wavelengthsselected for implementing either NRZ or PAM4 encoding protocolelectrical/optical signal conversion. The optical signals are modulatedby internal multi-segmented MZMs for transmission to an optical outputport via a fiber-interface. Conversely, an optical input port associatedwith the fiber-interface is configured to receive the optical signal andhave it detected by built-in photodetector (PD) per wavelength. The PDsare made of germanium and integrated onto the SiPho die directly. Thefiber-interface comprises a plurality of v-grooves, each of thev-grooves being coupled to a mode adaptor. The receive lane moduleincludes at least a PAM driver configured to drive the DFB laser insidethe optical module. The transmit lane module includes at least aPAM-enabled TIA for processing the received analog current signalconverted by the PD per wavelength.

In a specific embodiment, the integrated apparatus is packaged with aQSFP format interface with 28 pins capable of handling 4 wavelengthsoptical signal transmission with 28 GBaud rate for 100 G system. It isfurther upgradable to handle 4 wavelengths optical transmission with 56GBaud rate for 400 G system. The MZMs in the optical module and PAMdriver in the transmit lane module are capable of operating in both NRZand PAM4 encoding protocol for converting electrical signal to opticalsignal at any selected wavelength in either a CWDM channel or a DWDM 50GHz grid channel. The driver and TIA are made from 28 nm CMOS basedtechnology and still upgradable.

FIG. 10 is a simplified diagram illustrating a silicon photonics opticalmodule chip layout according to an embodiment of the present invention.This diagram is merely an example, which should not unduly limit thescope of the claims. One of ordinary skill in the art would recognizemany variations, alternatives, and modifications. As shown, up to 4laser devices configured to generate four lights with correspondingwavelength λ1, λ2, λ3, and λ4 are laid in the central region occupyingmajor area of the module. Each light with corresponding wavelength isguided through separate Si-based waveguides to a corresponding Si-basedMZ linear segmented modulator. The modulated light signal is thenmultiplexed by a MUX device and sent to a single transmit waveguide withall four wavelengths. The transmit waveguide is configured to couplewith a single fiber for optical transmission. Separately, a receivingwaveguide is configured to couple with a single fiber to receive anoptical signal carrying four wavelengths, λ1, λ2, λ3, and λ4. A DEMUXdevice is implemented to de-multiplex the received optical signal intofour individual lights with corresponding wavelength λ1, λ2, λ3, and λ4which are respectively detected by four high-speed photodetectors (PDs).

FIG. 11 is a simplified diagram of a modulation driver device accordingto an embodiment of the present invention. This diagram is merely anexample, which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. As shown, a modulation driver device 1100 includes acontrol block 1110, an encoder 1120, a pseudo random binary sequence(PRBS) signal generator 1130, and a distributed MZM configuration 1140.In particular, the control block 1110 is configured to receive a pair ofPAM_En code and PRBS_En code from a binary select table to respectivelyoperate the (PAM or NRZ) encoder 1120 and the PRBS signal generator 1130in a corresponding mode. The PAM encoder 1120 is configured to directlycouples with the distributed MZM configuration 1140 for controlling a MZmodulator inside the optical module of the integrated apparatus toprovide modulation based on received 28 Gbit/s CDR-processed electricsignal using PAM4 (or NRZ) encoding to a laser light generated by a DFBlaser device. The MZ modulator is substantially similar to one shown inFIG. 10 as a segmented modulator. The PRBS generator 1130 is to supply aknown binary sequence used as a test high-speed clock signal when makingbit error rate measurements. With the distributed MZM configuration 1140the driver device 1100 is a distributed driver comprising a parallelarray of a plurality of amplifier units 1141/1142 having a common biasvoltage Vbias, each of which is optimized to drive a single segment of amodulator in the optical module. In an implementation, each segment issubjected to about 0.5 MΩ-1.0 MΩ electrical isolation 1143 from itsneighbor due to about 10 μm˜20 μm pitch distance. Each segment itselfincludes a serial resistance 1144 of about 3Ω˜4Ω or induction 120 fF˜160fF due to segment length ranging from 350 μm˜450 μm. In an example,assuming that there are 9 segments in a MZ modulator, correspondinglythe distributed MZM driver configuration 1140 has 9 amplifier units1141/1142 with an isolation 1143 per pitch and a serial resistance 1144properly set for respectively driving each segment of the MZ modulator.

FIG. 12 is a simplified diagram illustrating a control scheme for MZmodulator according to an embodiment of the present invention. Thisdiagram is merely an example, which should not unduly limit the scope ofthe claims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. As shown, the MZ modulatoris a multi-segment modulator so that a distributed MZM controlconfiguration is used to set the MZ modulator bias at an ideal positionon Quadrature transfer curve. In particular, a middle electrode isapplied Vbias including a low frequency small amplitude dither signaland two side electrodes (per segment) are respectively set as a positiveand a negative electrode for a pair of p-n junctions such that thephases at the two arms (per segment) of the MZ modulator is justopposite to create a proper signal modulation. A forward biased sectionwith Itrim1 and Itrim2 on both arms is used to determine a base value ofVbias for the MZM. The dither signal is used along with the Vbias fortuning the modulation such that when the dither signal is detected usinga PD integrated with one of the arms the Vbias is tuned to minimize thedither signal at the output for locking the Vbias under a scheme of theQuadrature transfer curve.

FIG. 13 is a simplified diagram illustrating a preferred select tablefor modulation driver according to an embodiment of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. One of ordinary skill in the art wouldrecognize many variations, alternatives, and modifications. As shown, aselect table for both binary codes of PAM-En and PRBS_En is presented.Each of PAM_En and PRBS_En is selected from “0” or “1”. In anembodiment, for PAM_En=PRBS_En=0, a scheme with low-pass CDR output for10 to 28 GBaud/s electrical/optical signal conversion in NRZ encoding isselected. In another embodiment, for PAM_En=0, PRBS_En=1, a scheme withhigh speed clock signal accompanying a <50 GBaud/s electrical/opticalsignal conversion in NRZ encoding is selected. In yet anotherembodiment, for PAM_En=1, PRBS_En=0, a scheme with low-pass CDR outputfor 10 to 28 GBaud/s electrical/optical signal protocol conversion inPAM4 encoding is selected. In still another embodiment, forPAM_En=PRBS_En=1, a scheme with high speed clock signal accompanying a<50 GBaud/s electrical/optical signal conversion in PAM4 encoding isselected.

FIG. 14 is a simplified diagram illustrating PAM4 encoding schemeaccording to an embodiment of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. As shown, a PAM4 encodingscheme is proposed for mapping binary coded bit to Gray/thermometer codevia the segmented MZM sections. Assuming 9 equal thermometer coded MZMsections, the thermometer drives equally weighted segmented MZinterferometer drivers. For PAM4 signaling in the MZ interferometerdriver, there are four levels of optical output, representing two binarycoded bits: one LSB bit and one MSB bit, providing 2²=4 combinationstates of 0 and 1, e.g., 00, 01, 11, and 10. The Gray/Thermometer codingprovides better performance than binary weighting. As shown, minimum 3MZM sections are needed for mapping the two binary bits with four statesinto corresponding four thermometer codes of 000, 001, 011, and 111. Butthe 9 equal thermometer coded MZM sections can be grouped into 3sections to minimize device parasitics.

FIG. 15 is a simplified block diagram illustrating PAM4 encoder logicaccording to an embodiment of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. As shown, the tablesummarizes the scheme of binary to Gray/Thermometer encoding. Binarydigits include 0 and 1. For two digits bits, A and B, four combinationsexist as 00, 01, 11, and 10, corresponding to four PAM symbol of 1, 2,3, and 4. When it is encoded to Thermometer code, it is represented by 3elements X, Y, Z encoded as 000, 100, 110, and 111. In an embodiment,the value of X can be either a same value of A or B, the value if Y canonly be the same value of A, and the value of Z can be either the samevalue of A or reversed value of B. In a specific embodiment, a logiccircuit of the PAM4 Binary to Thermometer encoder is illustrated.

In an alternative example, the present invention includes an integratedsystem on chip device. The device is configured on a single siliconsubstrate member. The device has a data input/output interface providedon the substrate member and configured for a predefined data rate andprotocol. The device has an input/output block provided on the substratemember and coupled to the data input/output interface. In an example,the input/output block comprises a Serializer/Deserializer (SerDes)block, a clock data recovery (CDR) block, a compensation block, and anequalizer block, among others. The device has a signal processing blockprovided on the substrate member and coupled to the input/output block.In an example, the signal processing block is configured to theinput/output block using a bi-direction bus in an intermediary protocol.The device has a driver module provided on the substrate member andcoupled to the signal processing block. In an example, the driver moduleis coupled to the signal processing blocking using a uni-directionalmulti-lane bus. In an example, the device has a driver interfaceprovided on the substrate member and coupled to the driver module andconfigured to be coupled to a silicon photonics device. In an example,the driver interface is configured to transmit output data in either anamplitude modulation format or a combination of phase/amplitudemodulation format or a phase modulation format. In an example, thedevice has a receiver module comprising a transimpedance amplifier (TIA)block provided on the substrate member and to be coupled to the siliconphotonics device using predefined modulation format, and configured tothe digital signal processing block to communicate information to theinput output block for transmission through the data input/outputinterface. In an example, the device has a communication block providedon the substrate member and operably coupled to the input/output block,the digital signal processing block, the driver block, and the receiverblock, among others. The device has a communication interface coupled tothe communication block. The device has a control block provided on thesubstrate member and coupled to the communication block.

In an example, the signal processing block comprises a forward errorcorrection (FEC) block, a digital signal processing block, a framingblock, a protocol block, and a redundancy block, among others. Thedriver module is selected from a current drive or a voltage driver in anexample. In an example, the driver module is a differential driver orthe like. In an example, the silicon photonics device is selected froman electro absorption modulator or electro optic modulator, or aMach-Zehnder modulator. In an example, the amplified modulation formatis selected from non-return to zero (NRZ) format or pulse amplitudemodulation (PAM) format. In an example, the phase modulation format isselected from binary phase shift keying (BPSK) or nPSK. In an example,the phase/amplitude modulation is quad amplitude modulation (QAM). In anexample, the silicon photonic device is configured to convert the outputdata into an output transport data in a wave division multiplexed (WDM)signal. In an example, the control block is configured to initiate alaser bias or a modulator bias. In an example, the control block isconfigured for laser bias and power control of the silicon photonicsdevice. In an example, the control block is configured with a thermaltuning or carrier tuning device each of which is configured on thesilicon photonics device. In an example, the SerDes block is configuredto convert a first data stream of N into a second data stream of M.

In an example, the invention provides an integrated system on chipdevice. The device has a single silicon substrate member and a datainput/output interface provided on the substrate member and configuredfor a predefined data rate and protocol. In an example, the device hasan input/output block provided on the substrate member and coupled tothe data input/output interface. The input/output block comprises aSerDes block, a CDR block, a compensation block, and an equalizer block,among others. The device has a signal processing block provided on thesubstrate member and coupled to the input/output block. In an example,the signal processing block is configured to the input/output blockusing a bi-direction bus in an intermediary protocol. In an example, thedevice has a driver module provided on the substrate member and coupledto the signal processing block. The driver module is coupled to thesignal processing blocking using a uni-directional multi-lane bus. In anexample, the device has a driver interface provided on the substratemember and coupled to the driver module and configured to be coupled toa silicon photonics device. The driver interface is configured totransmit output data in either an amplitude modulation format or acombination of phase/amplitude modulation format or a phase modulationformat in an example. The device has a receiver module comprising a TIAblock provided on the substrate member and to be coupled to the siliconphotonics device using predefined modulation format, and configured tothe digital signal processing block to communicate information to theinput output block for transmission through the data input/outputinterface. In an example, the device has a communication block providedon the substrate member and operably coupled to the input/output blockand the digital signal processing block, the driver block, and thereceiver block, and others, although there may be variations. In anexample, the device has a communication interface coupled to thecommunication block and a control block provided on the substrate memberand coupled to the communication block. In an example, the control blockis configured to receive and send instruction(s) in a digital format tothe communication block and being configured to receive and send signalsin an analog format to communicate with the silicon photonics device.

In an example, the present invention provides a monolithicallyintegrated system on chip device configured for a multi-rate andselected format of data communication. In an example, the device has asingle silicon substrate member. The device has a data input/outputinterface provided on the substrate member and configured for apredefined data rate and protocol. In an example, the data input/outputinterface is configured for number of lanes numbered from four to onehundred and fifty. The device has an input/output block provided on thesubstrate member and coupled to the data input/output interface, whichhas a SerDes block, a CDR block, a compensation block, and an equalizerblock. In an example, the SerDes block is configured to convert a firstdata stream of N into a second data stream of M. In an example, each ofthe first data stream has a first predefined data rate at a first clockrate and each of the second data stream having a second predefined datarate at a second clock rate. As used herein the terms “first” and“second” do not necessarily imply order and shall be construed broadlyaccording to ordinary meaning. In an example, the device has a signalprocessing block provided on the substrate member and coupled to theinput/output block. The signal processing block is configured to theinput/output block using a bi-direction bus in an intermediary protocolin an example. The device has a driver module provided on the substratemember and coupled to the signal processing block. In an example, thedriver module is coupled to the signal processing blocking using auni-directional multi-lane bus. In an example, the device has a driverinterface provided on the substrate member and coupled to the drivermodule and configured to be coupled to a silicon photonics device. In anexample, the driver interface is configured to transmit output data ineither an amplitude modulation format or a combination ofphase/amplitude modulation format or a phase modulation format. Thedevice has a receiver module comprising a TIA block provided on thesubstrate member and to be coupled to the silicon photonics device usingpredefined modulation format, and is configured to the digital signalprocessing block to communicate information to the input output blockfor transmission through the data input/output interface. In an example,the device has a communication block provided on the substrate memberand operably coupled to the input/output block, the digital signalprocessing block, the driver block, and the receiver block, and others,although there can be variations. In an example, the device has acommunication interface coupled to the communication block and a controlblock provided on the substrate member and coupled to the communicationblock.

In an example, the present invention provides a monolithicallyintegrated system on chip device configured for a multi-rate andselected format of data communication. In an example, the device has asingle silicon substrate member. The device has a data input/outputinterface provided on the substrate member and configured for apredefined data rate and protocol. In an example, the data input/outputinterface is configured for number of lanes numbered from four to onehundred and fifty, although there can be variations. In an example, thedevice has an input/output block provided on the substrate member andcoupled to the data input/output interface. In an example, theinput/output block comprises a SerDes block, a CDR block, a compensationblock, and an equalizer block, among others. In an example, the SerDesblock is configured to convert a first data stream of X into a seconddata stream of Y, where X and Y are different integers. Each of thefirst data stream has a first predefined data rate at a first clock rateand each of the second data stream has a second predefined data rate ata second clock rate in an example. In an example, the device has asignal processing block provided on the substrate member and coupled tothe input/output block. In an example, the signal processing block isconfigured to the input/output block using a bi-direction bus in anintermediary protocol. In an example, the device has a driver moduleprovided on the substrate member and coupled to the signal processingblock. In an example, the driver module is coupled to the signalprocessing blocking using a uni-directional multi-lane bus configuredwith N lanes, whereupon N is greater than M such that a differencebetween N and M represents a redundant lane or lanes. In an example, thedevice has a mapping block configured to associate the M lanes to aplurality of selected laser devices for a silicon photonics device. Thedevice also has a driver interface provided on the substrate member andcoupled to the driver module and configured to be coupled to the siliconphotonics device. In an example, the driver interface is configured totransmit output data in either an amplitude modulation format or acombination of phase/amplitude modulation format or a phase modulationformat. In an example, the device has a receiver module comprising a TIAblock provided on the substrate member and to be coupled to the siliconphotonics device using predefined modulation format, and configured tothe digital signal processing block to communicate information to theinput output block for transmission through the data input/outputinterface. The device has a communication block provided on thesubstrate member and operably coupled to the input/output block, thedigital signal processing block, the driver block, and the receiverblock, among others. The device has a communication interface coupled tothe communication block and a control block provided on the substratemember and coupled to the communication block.

In an example, the device has an integrated system on chip device. Thedevice has a single silicon substrate member and a data input/outputinterface provided on the substrate member and configured for apredefined data rate and protocol. In an example, the device has aninput/output block provided on the substrate member and coupled to thedata input/output interface. In an example, the input/output blockcomprises a SerDes block, a CDR block, a compensation block, and anequalizer block, among others. The device has a signal processing blockprovided on the substrate member and coupled to the input/output block.The signal processing block is configured to the input/output blockusing a bi-direction bus in an intermediary protocol. The device has adriver module provided on the substrate member and coupled to the signalprocessing block. In an example, the driver module is coupled to thesignal processing blocking using a uni-directional multi-lane bus. In anexample, the device has a driver interface provided on the substratemember and coupled to the driver module and configured to be coupled toa silicon photonics device. In an example, the driver interface isconfigured to transmit output data in either an amplitude modulationformat or a combination of phase/amplitude modulation format or a phasemodulation format. In an example, the device has a receiver modulecomprising a TIA block provided on the substrate member and to becoupled to the silicon photonics device using predefined modulationformat, and configured to the digital signal processing block tocommunicate information to the input output block for transmissionthrough the data input/output interface. In an example, the device has acommunication block provided on the substrate member and operablycoupled to the input/output block, the digital signal processing block,the driver block, and the receiver block, and among others. The devicehas a communication interface coupled to the communication block and acontrol block provided on the substrate member and coupled to thecommunication block. In an example, the device has a variable bias blockconfigured with the control block. In an example, the variable biasblock is configured to selectively tune each of a plurality of laserdevices provided on the silicon photonics device to adjust for at leasta wavelength of operation, a fabrication tolerance, and an extinctionratio.

In an example, the present invention provides an integrated system onchip device having a self test using a loop back technique. In anexample, the device has a self-test block provided on the substrate, theself test block being configured to receive a loop back signal from atleast one of the digital signal processing block, the driver module, orthe silicon photonics device. In an example, the self test blockcomprises a variable output power switch configured to provide a stressreceiver test from the loop back signal.

In an example, the invention provides an integrated system-on-chipdevice having a redundant laser or lasers configured for each channel.In an example, the device has a plurality of laser devices configured onthe silicon photonics device. At least a pair of laser devices isassociated with a channel and coupled to a switch to select one of thepair of laser devices to be coupled to an optical multiplexer to providefor a redundant laser device.

In a specific embodiment, the present invention provides an integratedsystem-on-chip device having a built-in self test technique. In anexample, the integrated apparatus has a self test block configuredthrough ASIC interface on the transmit lane module coupled with siliconphotonics optical module and to be operable during a test operation. Inan example, the self test block comprises a broad band source configuredto emit electromagnetic radiation from 1200 nm to 1400 nm or 1500 to1600 nm to a multiplexer device. In an example, the broad band sourcecan be a LED or other suitable device. The self test block is configuredto digitally monitor the performance of the transmit lane module andgenerate digital data diagnostics inside the integrated apparatusthrough the ASIC interface. This diagnostic information includestemperature of the module, transmitter optical power, receiver opticalpower, error rate of the received signal through the FEC, level ofdistortion in the received signal through the DSP, etc. The self testblock also includes a self test output configured to a spectrum analyzerdevice external to the silicon photonics optical module.

While the above specification is a full description of the specificembodiments, various modifications, alternative constructions andequivalents may be used. Therefore, the above description andillustrations should not be taken as limiting the scope of the presentinvention which is defined by the appended claims.

What is claimed is:
 1. An integrated communication apparatus comprising:a DMUX device configured to receive an incoming optical signal with atleast 4 multiplexed wavelengths to get at least 4 de-multiplexedsignals; multiple photo-detectors to convert the de-multiplexed signalsto current signals; a receive lane module comprising a transimpedanceamplifier (TIA) to amplify the current signals, an analog-to-digitalconverter (ADC) to convert the current signals to digital signals, adigital signal processor (DSP) to process the digital signals; atransmit lane module for generating electrical signals, the transmitlane module comprising a forward error correction device (FEC) andencoder; one or more DFB laser devices for producing laser signals basedon the electrical signals, the DFB laser devices being characterized bya relative intensity noise (RIN) level of less than −140 dB/Hz; one ormore optical modulators configured to modulate the laser signals togenerate modulated optical signals; and a MUX device configured tomultiplex the modulated optical signals and to output a multiplexedoptical signal.
 2. The integrated communication apparatus of claim 1wherein the DEMUX device comprises one or more silicon-based delay-lineinterferometers (DLIs), each DLI being configured to interleave theincoming optical signal from one fiber into two waveguides each with ade-multiplexed signal in different wavelength.
 3. The integratedcommunication apparatus of claim 1 wherein the multiple photodetectorsare configured to respectively convert the at least 4 de-multiplexedsignals with different wavelengths.
 4. The integrated communicationapparatus of claim 1 wherein the at least 4 de-multiplexed wavelengthscomprise a predetermined channel spacing selected from 50 GHz or 100GHz.
 5. The integrated communication apparatus of claim 1 wherein thereceive lane module further comprises a Tx clock and data recoverydevice (Tx-CDR) configured to remove jitter within the digital signalsbefore transmitting to Ethernet.
 6. The integrated communicationapparatus of claim 5 wherein the ADC and the DSP are PAM-N enabledencoding format, selecting from PAM4, PAM8, or PAM16, or NRZ encodingformat.
 7. The integrated communication apparatus of claim 1 wherein thetransmit lane module further comprises a receiving Rx-CDR to handle anelectrical signal received from an electrical interface.
 8. Theintegrated communication apparatus of claim 7 wherein the transmit lanemodule further comprises a driver (DRV) using PAM-N or NRZ enabledencoding format to control the one or more DFB laser devices and the oneor more optical modulators to generate the modulated optical signals. 9.The integrated communication apparatus of claim 8 wherein the one ormore optical modulators comprise silicon-based Mach Zehnder linearsegmented modulator.
 10. The integrated communication apparatus of claim9 wherein the silicon-based Mach Zehnder modulator operates in a carrierdepletion mode.
 11. The integrated communication apparatus of claim 8wherein the one or more optical modulators comprise a distributedconfiguration driven by the driver comprising a parallel array of aplurality of amplifiers, each of which is optimized with a PAM encoderto drive a single segment of a modulator.
 12. The integratedcommunication apparatus of claim 1 wherein the MUX device comprises oneor more DLIs, each DLI being a 2-to-1 power combiner.
 13. The integratedcommunication apparatus of claim 1 further comprises a control modulecomprising power supplies, a microcontroller, and ASIC chips.
 14. Theintegrated communication apparatus of claim 1 further comprises anelectrical interface.
 15. The integrated communication apparatus ofclaim 14 wherein the electrical interface is configured with 4×10 G/bitsQuad Small Form-factor Pluggable (QSFP) compact, hot-pluggable format.16. The integrated communication apparatus of claim 1 further comprisingan optical amplifier and a dispersion compensation module for retainingdata integrity of the multiplexed optical signal.
 17. An integratedcommunication apparatus for 100 Gb/s data rate system comprising: a DMUXdevice configured to interleave an incoming optical signal from a singlefiber to two lights respectively with two channel wavelengths; a dualPIN photodetector for separately detecting the two lights andrespectively convert to two current signals; a receive lane modulecomprising a dual linear TIA and dual PAM-enabled ADC/DSP device forprocessing the two current signals and generating corresponding digitalsignals; a transmit lane module comprising a dual PAM driver and aforward error correction device (FEC) to handle electrical signalsreceived from an electrical interface; two DFB laser devices forproducing two laser signals with two wavelengths based on the electricalsignals, the DFB laser devices being characterized by a relativeintensity noise (RIN) level of less than −140 dB/Hz; a dual opticalmodulator comprising a PAM encoder driven by the dual PAM driver tomodulate the two laser signals to generate two modulated opticalsignals; and a MUX device configured to combine the two modulatedoptical signals to one output signal into an output fiber.
 18. Theintegrated communication apparatus of claim 17 wherein the electricalinterface comprises an Ethernet configured to provide an electricalsignal in 4×25 G CAUI-4 format.
 19. The integrated communicationapparatus of claim 17 wherein the transmit lane module further comprisesa Rx correct data recovery (Rx-CDR) device and a forward errorcorrection (FEC) device coupled with an encoder to handle the electricalsignal from the Ethernet; the receive lane module further comprises aforward error correction (FEC) device coupled with an decoder and Txcorrect data recovery (Tx-CDR) device to remove jitter within thedigital signals to be sent to the Ethernet.
 20. The integratedcommunication apparatus of claim 17 wherein the dual PAM driver isimplemented with an encoder in 28.125 GBaud PAM4 format for 100 Gbit/sdata rate optical transmission over one of 4 CWDM channels or 40 DWDMchannels with 100 GHz spacing.